SIMULATION OF THIN-FILM DEODORIZERS IN PALM OIL REFINING

As the need for healthier fats and oils (natural vitamin and trans fat contents) and interest in biofuels are growing, many changes in the world's vegetable oil market are driving the oil industry to developing new technologies and recycling traditional ones. Computational simulation is widely used in the chemical and petrochemical industries as a tool for optimization and design of (new) processes, but that is not the case for the edible oil industry. Thin-film deodorizers are novel equipment developed for steam deacidification of vegetable oils, and no work on the simulation of this type of equipment could be found in the open literature. This paper tries to fill this gap by presenting results from the study of the effect of processing variables, such as temperature, pressure and percentage of stripping steam, in the final quality of product (deacidified palm oil) in terms of final oil acidity, the tocopherol content and neutral oil loss. The simulation results have been evaluated by using the response surface methodology. The model generated by the statistical analysis for tocopherol retention has been validated by matching its results with industrial data published in the open literature.

PRACTICAL APPLICATIONS

This work is a continuation of our previous works ( Ceriani and Meirelles 2004a, 2006 ; Ceriani et al. 2008 ), dealing with the simulation of continuous deodorization and/or steam deacidification for a variety of vegetable oils using stage-wised columns, and analyzing both the countercurrent and the cross-flow patterns. In this work, we have studied thin-film deodorizers, which are novel equipment developed for steam deacidification of vegetable oils. Here, we highlight issues related to final oil product quality and the corresponding process variables.     

RECOVERY OF PALM CAROTENE FROM PALM OIL AND HYDROLYZED PALM OIL BY ADSORPTION COLUMN CHROMATOGRAPHY

Crude palm oil and crude palm olein were hydrolyzed with lipase from Candida rugosa to produce a free fatty acid (FFA) rich oil. The percentages of FFA produced and carotene degradation after the hydrolysis process were determined. The palm oil and hydrolyzed palm oil were subsequently subjected to column chromatography. Diaion HP-20 adsorbent was used for reverse phase column chromatography at 50C. Isopropanol or ethanol, and n-hexane were used as the first and second eluting solvents, respectively. The objective of hydrolyzing the palm oil was to produce more polar FFA-rich oil in order to enhance the nonpolar carotene bind to the nonpolar HP-20 adsorbent in the column chromatography process. Hydrolyzing palm oil with lipase from Candida rugosa gave 30- and 60-fold, respectively, of FFA in the crude palm oil and crude palm olein in 24 h at 50C. Approximately, 15.56 and 17.48% of carotene degraded in crude palm oil and crude palm olein, respectively. For column chromatography, using isopropanol or ethanol as the first eluting solvent, unhydrolyzed oil and hydrolyzed oil showed the carotene recovery infraction two (carotene-rich fraction) of about 36–37 and 90–96%, respectively. Over 90% of carotene recovery was obtained from     

RANDOMNESS TEST OF FATTY ACIDS DISTRIBUTION IN TRIACYLGLYCEROL MOLECULES OF PALM OIL

For food purposes, the palm oil is generally fractionated to solid (stearin) and liquid (olein) fractions. Distribution of fatty acids in triacylglycerols of palm oil determines the fate of fractionation in terms of yield and quality of the products, specifically the liquid fraction or olein. The more trisaturated and triunsaturated and the less mono- and disaturated will yield higher and better quality olein. There are six types of fatty acids found in the palm oil, but only 14 combinations are found in the triacylglycerols. In this study, such combinations were statistically tested to determine whether or not the fatty acids are randomly distributed, and if it was not, toward which direction the regulatory agent works. The distribution of fatty acids in the palm oil triacylglycerols was found to be nonrandomly distributed. Unfortunately, the palm tended to form 11.98% higher disaturated triacylglycerols, −7.4% less triunsaturated, and −4.25% less trisaturated compared to when the arrangement was random. If manipulation could be induced in such a way that the synthesis of triacylglycerols becomes random, the triunsaturated and trisaturated triacylglycerol proportion expectedly would increased to 12.57% and 12.43%, respectively. Such manipulation can be done in the plant through genetic engineering, or in the harvestedpuit through application of stimulant, or in the oil through chemical or enzymatic transesterification.     

MONITORING OF TRANSESTERIFICATION OF PALM OIL BY DIFFERENTIAL SCANNING CALORIMETRY

Chemical transesterification was conducted to obtain triacylglycerol ( TG) containing maximum concentrations of trisaturated and triunsaturated TG in palm oil. Catalyst (sodium methoxide) concentration of 0.1–0.5%, reaction temperature of 50–92C and reaction time of 30–480 min were applied in 20 treatments. Concentrations of trisaturated and triunsaturated TG, as well as melting points and iodine values were monitored by differential scanning calorimetric (DSC) techniques. The results showed that maximum trisaturated and triunsaturated TG achieved for refined-bleached-deodorized (RBD) palm oil were 17.10 and 7.50%, respectively, using 0.42% catalyst, at 58C in 389 min. These amounts were higher compared to control (untransesterified) RBD palm oil i.e 7.45 and 4.92%, respectively. The melting points of the products were higher compared to the control, while the iodine values were not significantly changed in all of the treatments.     

PROCESSING OF CRUDE PALM OIL WITH CERAMIC MICROFILTRATION MEMBRANE

Membrane separation technology offers a potential application in the processing of crude palm oil. Ceramic membranes with different pore diameters (0.45 and 0.2 micron) were used to conduct the study on micromembrane process. Quality parameters of membrane-processed oils examined included free fatty acid (FFA), carotene, fatty acid composition (FAC), phosphorus and iron contents. The effect of operating parameters such as transmembrane pressure, feed flow and time on permeate flux were evaluated. It was found that 'Ceraflo'ceramic membrane with a pore size of 0.45 micron was only able to reject 14% of phosphorus from the crude oil. Ceramic membrane with pore size of 0.2 micron showed a better phosphorus rejection of 56.8%. The permeate was found to contain 7.13 ppm of phosphorus. The 0.2 micron membrane was also able to remove more than 80% of the iron from crude palm oil. Pore sizes for both membranes were not small enough to remove other components such as FFA, and carotene. Both membranes showed a similar trend in which the permeate flux increased with transmembrane pressure and feed flow until a certain limit where the flux declined with increasing pressure and feed flow. The limits in transmembrane pressures for membrane with pore sizes of 0.45 and 0.2 micron were 1.65 and 1.25 bar, respectively. Whereas the limits in feed flow for 0.45 micron and 0.2 micron membranes were 9.2 and 9.8 L/min     

OPTIMIZATION OF CHEMICAL TRANSESTERIFICATION OF PALM OIL USING RESPONSE SURFACE METHODOLOGY

The effect of catalyst concentration (0.1–0.5% methoxide powder), temperature (50–92C), and time (30–480 min) of chemical transesterification was studied to determine the optimum condition for maximizing concentration of triunsaturated and trisaturated triacylglycerols (TG) in palm oil. TG compositions of the oil were analysed using high-performance liquid chromatography. The optimum condition of the process was determined using statistical response surface methodology. The results showed that the triunsaturated and trisaturated TG responses followed a second order form of the treatments with R²= 0.83 and 0.85, respectively. The triunsaturated TG reached a maximum concentration by using 0.36% catalyst at 78C and 360 min reaction time, whereas the trisaturated TG with 0.36% catalyst at 81C and 325 min reaction time. Considering the two responses, it was concluded that the overall optimum condition could be achieved at 0.36% of catalyst at 78–81C and 325–360 min reaction time. Such conditions increased trisaturated TG in palm oil by 2.34 times and triunsaturated TG by 1.54 times.     

RAPID DETERMINATION OF PEROXIDE VALUE IN CRUDE PALM OIL PRODUCTS USING FOURIER TRANSFORM INFRARED SPECTROSCOPY

A rapid Fourier transform infrared (FTIR) spectroscopic technique coupled with fixed NaCl cell (1 mm pathlength) was developed to measure peroxide value (PV) in crude palm oil (CPO) and crude palm kernel oil (CPKO). Calibration standards were prepared by oxidizing CPO in a fermentor at 60C over a period of 24 h. A partial least squares (PLS) calibration model for predicting PV was developed based on the 3710–3210 cm^-1spectral region with reference to a single-point baseline at 3710 cm^-1. The optimization of calibration factors was guided by the predicted residual error sum of squares (PRESS) test. The standard deviation (SD) of the calibration obtained was 0.46 PV over the range of 0.51–17.82 PV and the correlation coefficient (R2) was 0.998. The model was validated with an independent set of samples consisting of both laboratory and field samples. The overall SD for the validation set was sligthly higher (SD = 1.46 PV) with R2 of 0.989. Thus, it was demonstrated that PV measured by FTIR techniques was comparable to that obtained by the chemical method. The FTIR method has the     

PROCESS INTENSIFICATION OF MEMBRANE SYSTEM FOR CRUDE PALM OIL PRETREATMENT

In the study conventional refining, microfiltration and ultrafiltration processes have been used experimentally to pretreat crude palm oil (CPO) samples with the aim of moving from the usual huge refinery plant to a more process integrated membrane module at ultrascale size that will even perform better than the former. Reduction of phosphorus for the membrane‐permeate of 43.4% was higher than that of bleached oil of 34.4%. When ceramic membranes with pore diameters of 0.45 µm and 0.2 µm were used in microfiltration, it was found that membrane with pore size of 0.45 µm was able to reject 14% of phosphorus, while ceramic membrane with pore size of 0.2 µm showed better phosphorus rejection of 56.8%. Upon applying ceramic membrane with pore sizes of 20 nm and 50 nm, 78.1% and 60% of phosphorus were rejected, respectively. Attributed to the superior performance of the membrane with 20 nm pore size over other membranes and conventional refining method on phosphorus content, a simulation study thus made, showed that the average slurry volume after about 22‐min runs for membrane with pore sizes of 0.45 µm, 0.2 µm, 50 nm and 20 nm, and the average slurry volumes are 0.05, 0.09, 0.13 and 0.18 m ³ , respectively. The percentage decrease between membrane pore size of 0.45 µm and 0.2 µm; 0.45 µm and 50 nm; and 0.45 µm and 20 nm are 73, 49 and 24%, respectively. The ultrafiltration achieved order of process miniaturization of about 10 ² ?10 ³ , which is in accordance with literature. This is a considerable size reduction in the process size, which reflects the magnitude of slurry volume that can be produced within a given time and meets every standard for process intensification through simulated process miniaturization.     

PRODUCTION OF PALM OIL REFERENCE MATERIALS FOR THE DETERMINATION OF SOLID FAT CONTENT

ABSTRACT

Three palm oil reference materials were produced for solid fat content analysis employing the Malaysian Palm Oil Board (MPOB) Test Methods. Thirteen laboratories participated in the characterization study, where the solid fat content in palm oil, palm olein and palm stearin were identified at temperature range from 0 to 45C. The consensus values were calculated based on the acceptability of statistical results from collaborating laboratories. Both of the consensus values and their uncertainties (%) for each reference material are as follows: 71.12 ± 1.82% (0C), 54.07 ± 1.05% (10C), 37.44 ± 0.88% (15C), 24.18 ± 1.09% (20C), 13.32 ± 0.86% (25C), 7.64 ± 0.28% (30C), 4.05 ± 0.14% (35C) and 1.25 ± 0.49% (40C) for SFC of palm oil, 66.32 ± 1.93% (0C), 43.53 ± 1.32% (10C), 22.50 ± 0.78% (15C), 6.68 ± 1.14% (20C) and 1.40 ± 0.35% (25C) for SFC of palm olein, and 78.09 ± 1.23% (0C), 67.66 ± 0.71% (10C), 56.29 ± 1.18% (15C), 44.37 ± 1.13% (20C), 30.22 ± 1.25% (25C), 20.08 ± 0.58% (30C), 13.72 ± 0.32% (35C), 8.97 ± 0.72% (40C) and 5.06 ± 0.41% (45C) for solid fat content of palm stearin.

PRACTICAL APPLICATIONS

The implementation of the ISO 17025 accreditation should be encouraged for testing laboratories to assure the traceability of analysis performed. This accreditation requires the use of certified reference materials to ensure that the analysis performed is parallel to the ISO 17025 standards. However, the unavailability of palm oil reference materials will affect the implementation of such standards for laboratories that are performing palm oil analyses. Hence, this study is aimed to characterize and certify the palm oil reference materials for determination of solid fat content. The establishment of this study is hoped to increase the credibility of laboratories, which are involved in the palm oil analysis. This will also promote the Malaysia Palm Oil Board as a center for the certification of palm oil reference materials.